Prof. Kaoru Teranishi, assistant professor in the Department of Information and Physical Sciences at The University of Osaka, visited CDSL on August 31, 2026, and gave a seminar entitled “Secure Two-Party Matrix Multiplication from Lattices and Its Application to Encrypted Control.”
Prof. Teranishiʼs research lies at the intersection of control theory and cryptography, with a particular focus on secure and privacy-preserving computation for control and optimization.
In his seminar, Prof. Teranishi introduced a secure two-party computation framework for encrypted control. The key idea is to outsource matrix computations arising in linear control laws to two computing parties while hiding sensitive information, including system states, control inputs, and feedback gains. The proposed protocol combines secret sharing with lattice-based cryptographic techniques to perform approximate matrix multiplication with only one round of communication between the two parties. He also discussed how the method can reduce the online computational burden on the client and analyzed the approximation errors arising from secure computation and fixed-point representation.
The topic is closely connected to the research interest of CDSL. Our group has studied encrypted control, including dynamic controllers operating directly on homomorphically encrypted data, efficient implementations based on LWE and Ring-LWE cryptosystems, and more recently privacy-preserving optimization and model predictive control. These studies share a common objective with Prof. Teranishiʼs work: making secure control not only theoretically sound, but also computationally practical for real-time dynamical systems. CDSL members have also collaborated with Prof. Teranishi on recent research in privacy-preserving control and learning, making his visit a particularly valuable opportunity to exchange ideas on the interface between control theory and cryptography.
We sincerely thank Prof. Teranishi for sharing his recent research and for the stimulating discussions with CDSL members. We look forward to continuing our academic exchange and exploring further opportunities for collaboration in secure and privacy-preserving control.